Plate heat exchanger

ABSTRACT

The invention relates to a plate heat exchanger ( 1 ) including a first and second end plate ( 2, 3 ), and a core of heat exchanger plates ( 4 ) arranged between the first and second end plate ( 2, 3 ), whereby a plurality of threaded tightening bolts ( 5   a,    5   b,    5   c ) extend between the first and second end plate ( 2, 3 ) and are arranged, with the aid of nuts ( 6 ) or the like, to hold these plates at a desired distance from each other in order to hold the core of heat exchanger plates together, wherein at least one guiding element ( 7, 7   a,    7   b ) for guiding the first end plate ( 2 ) and the heat exchanger plates ( 4 ) relatively the second end plate ( 3 ) is releasably arranged on at least one of the threaded tightening bolts ( 5   a,    5   b ), which guiding element ( 7   a ) extends through an aperture ( 8 ) in the first end plate ( 2 ), where the at least one guiding element ( 7   a,    7   b ) is provided with a through-hole ( 9 ) to receive the at least one of the threaded tightening bolts ( 5   a,    5   b ) and an external geometry ( 10 ) corresponding to a cut-out ( 11 ) of the heat exchanger plates ( 4 ) and the first end plate ( 2 ).

AREA OF INVENTION

The present invention refers generally to plate heat exchangers allowinga heat transfer between two fluids at different temperature for variouspurposes. Specifically, the invention relates to a plate heat exchangercomprising a first end plate, a second end plate and a package of heatexchanger plates placed between the frame plate and the pressure plate.A plurality of threaded tightening bolts extend between the first endplate and the second end plate and are arranged to hold with the aid ofnuts or the like these plates at a desired distance from each other inorder to hold the package of heat exchanger plates together.

BACKGROUND OF INVENTION

Plate heat exchangers are normally provided with a frame plate, apressure plate, also called end plates, and a package of heat exchangerplates disposed adjacent to one another and placed between the frameplate and the pressure plate. Gaskets are disposed between the heatexchanger plates. The gaskets are accommodated in gasket grooves on theheat exchanger plate, which are formed during the form-pressing of theheat exchanger plates. Plate heat exchangers further comprise inlet andoutlet ports, which extend through the plate package, for handling twoor more media in the plate heat exchanger. A plurality of threadedtightening bolts extend between the frame plate and the pressure plateand are arranged to hold with the aid of nuts or the like these platesat a desired distance from each other in order to hold the package ofheat exchanger plates together and to ensure that the plate heatexchanger does not leak.

Heat exchanger plates are normally made by form-pressing of sheet metaland are disposed in the plate package in such a way as to form firstplate intermediate spaces, which communicate with the first inlet portand the first outlet port, and second plate intermediate spaces whichcommunicate with the second inlet port and the second outlet port. Thefirst and second plate intermediate spaces are disposed alternately inthe plate package.

The design of heat exchanger plate for plate heat exchangers aims to useas much as possible of heat transfer or heat exchange area for the heatexchange between two or more media, but it also needs take in accounthow the gaskets can be applied on the heat exchanger plate to besecurely fastened and to fulfil its seal functionality. The location ofthe threaded tightening bolts are preferably selected to achieve a plateheat exchanger not exposed too much stresses.

SE-C-171 499 shows a plate heat exchanger with a frame plate, a pressureplate, a package of heat exchanger plates, two tie bars as well as aspecial supporting device. The frame plate and the supporting device areboth provided with feet. Through influence from among other things theyokes a pressure is created on the pressure plate and the package ofplates is kept together. The construction shows the disadvantage thatboth the supporting device and the pressure plate with necessity arecreated in the form of a very strong construction. Further on theauxiliary carrying bar to support plates in connection with mounting anddemounting of the heat exchanger constitutes an unnecessarycomplication.

In EP-B1-1 027 571 is shown another plate heat exchanger, wheretightening bolts have been integrated into the carrying bar and theguide bar, and creates a guiding element for the pressure plate and theheat exchanger plates. The localization of the tightening bolts isthereby more optimal to resist the forces laid onto the plate heatexchanger during operation. The guiding element is surrounded by aprotecting sleeve extending from the frame plate to the pressure plateand protecting the threads of the guiding element from engagement withthe heat exchanger plates. The guiding element is also arranged to beconnected to a supporting device situated at a substantial distance fromthe pressure plate.

The drawbacks with the above solutions are that the stresses are andforces are too great if the solutions are applied on larger plate heatexchangers.

DISCLOSURE OF INVENTION

The object of the present invention is to create a construction which isgives an optimal load distribution over the plate heat exchanger stillbeing cheaper and less complicated to manufacture than the one describedabove.

The advantages are attained by using at least one guiding element forguiding the first end plate and the heat exchanger plates relatively thesecond end plate, and where the guiding element is releasably arrangedon at least one of the threaded tightening bolts. The guiding elementextends through an aperture and the at least one guiding element isprovided with a through-hole to receive the at least one of the threadedtightening bolts and an external geometry corresponding to a cut-out ofthe heat exchanger plates and the first end plate.

According to another aspect of the invention the plate heat exchanger isprovided with two guiding elements, a first guiding element arranged inan upper portion of the plate heat exchanger and a second guidingelement arranged in a lower portion of the plate heat exchanger. Thefirst and second guiding element can have an identical cross sectionprofile.

According to yet another aspect of the invention the second guidingelement further is provided with a guiding rail for movably receivingthe second guiding element.

According to still another aspect of the invention the guiding rail formovably receiving the second guiding element is fully or partiallysupported by the ground.

According to a further another aspect of the invention the at least oneguiding element includes two separate parts, and the at least oneguiding element and the guiding rail is made of an extrudable material.

According to a further another aspect of the invention a supportingdevice is releasably arranged at a considerable distance from the firstend plate at the end of the upper and lower tightening bolts, andextending between the upper and lower tightening bolts.

According to still another aspect of the invention the at least oneguiding element is movable along the tightening bolts and where one partof the guiding element can be removed as the heat exchanger plates arepressed together by the first end plate to form the operating plate heatexchanger, where after the removed one part of the guiding element canbe arranged on a free portion of the tightening bolt outside the plateheat exchanger.

According to another aspect of the invention the object is attained by aplate heat exchanger where the heat exchanger plates rest on the atleast one guiding element and where the first end plate rests on aguiding rail, upon which guiding rail the at least one guiding elementis movably received.

Further aspects of the invention are defined in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now to be explained more closely by means of adescription of various embodiments and with reference to the drawingsattached hereto.

FIG. 1 discloses a perspective view of a plate heat exchanger accordingto an embodiment of the invention;

FIG. 2 shows a side view of a plate heat exchanger according to anembodiment of the invention;

FIG. 3 discloses a partial view of a plate heat exchanger according toan embodiment of the invention;

FIG. 4 discloses a cross section view A-A of a plate heat exchangeraccording to an embodiment of the invention;

FIG. 5 discloses a first partial detailed view B of the plate heatexchanger of FIG. 4 according to an embodiment of the invention;

FIG. 6 discloses a second partial detailed view C of the plate heatexchanger of FIG. 4 according to an embodiment of the invention;

FIGS. 7 a-b show different views of a guiding element according to theinvention; and

FIGS. 8 a-b show different views of a guiding rail according to theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS

Heat exchangers are used for transferring heat between two fluidsseparated by a solid body. Heat exchangers can be of several types, themost common are spiral heat exchangers, tubular heat exchangers andplate heat exchangers. Plate heat exchangers are used for transferringheat between a hot and a cold fluid that are flowing in alternate flowpassages formed between a set of heat exchanger plates. The arrangementof heat exchanger plates defined above is enclosed between end platesthat are relatively thicker than the heat exchanger plates. The innersurface of each end plate faces the heat transfer plates.

FIGS. 1-2 disclose a schematic view of a plate heat exchanger 1comprising a number of compression-molded heat exchanger plates 4, whichheat exchanger plates 4 are provided in parallel to each other andsuccessively in such a way that they form a plate package. The platepackage is provided between a first end plate 2, also called pressureplate, and a second end plate 3, also called frame plate. Between theheat exchanger plates 4, first plate interspaces and second plateinterspaces are formed. The end plates 2 and 3 are pressed against theplate package and against one another by tightening bolts or tie bars 5a-c, which extend through the end plates 2 and 3, and which tighteningbolts 5 a-c are kept in place by nuts 6, 20.

The plate heat exchanger 1 comprises a first inlet port and a firstoutlet port for a first medium, and a second inlet port and a secondoutlet port for a second medium. The inlet and outlet ports extendthrough the second end plate 3 and the plate package. It is of coursealso possible for the inlet and outlet ports to be disposed on bothsides of the plate heat exchanger 1, i.e. on both end plates 2 and 3.The two medium may be led in the same or in opposite directions relativeto one another.

The heat exchanger plates 4 in the shown embodiment are disposed in sucha way in the plate package as to form first plate intermediate spaceswhich communicate with the first inlet port and the first outlet port,and second plate intermediate spaces, which communicate with the secondinlet port and the second outlet port. The first and second plateintermediate spaces are disposed alternately in the plate package. Theseparation of the plate intermediate spaces may be by gaskets extendingin gasket grooves formed during the form-pressing of the heat exchangerplates. The gaskets are usually made of a rubber or polymer material.The heat exchanger plates 4 are provided with a corrugated pattern toimprove the heat exchange between the two fluids.

To guide the heat exchanger plates 4, to protect the threaded tighteningbolts 5 a, 5 b from wear of the heat exchanger plates 4, to simplify theconstruction and to make the construction cheaper, there has beenprovided guiding elements 7, 7 a, 7 b on the uppermost and lowermost ofthe tightening bolts 5 a, 5 b.

Compared with state of the art plate heat exchanger the uppermost andlowermost of the tightening bolts 5 a, 5 b replace the traditionalcarrying and guiding bar, which otherwise serve to enable theopening/closing of the plate heat exchanger by enabling the first endplate 2 and the heat exchanger plates 4 to be moved along the carryingbar and the guiding bar while the plate heat exchanger is standing. Byproviding upper and lower guiding elements 7 a, 7 b that arranged on thetightening bolts 5 a-5 b, respectively, and where the guiding elements 7a, 7 b has an outer cross section geometry (see FIGS. 7 a-b) similar tothe traditional carrying bar the heat exchanger plates 4, having acut-out profile 11 corresponding to an lower portion of the guidingelement 7 a, 7 b having an external geometry 10, can be guided along theupper guiding element 7 a. The tightening bolts 5 a, 5 b are received inan aperture or through hole 9 of the guiding element 7 a, 7 b, whichthrough hole 9 extends along the entire longitudinal length of theguiding element 7 a, 7 b. The guiding element 7 a, 7 b is made of anextrudable material to make cheaper to manufacture and to lighten theconstruction. The extrudable material can be plastic, aluminum or anyother suitable construction material.

Further tightening bolts 5 c are present in a usual way between thesecond end plate 3 and the first end plate 2, and are placed in notchesor recesses at the edges of the second end plate 3 and the first endplate 2.

Since the guiding element 7 a, 7 b is made of an extrudable material itcannot withstand the same load as a corresponding metal construction.Therefore the load of the heat exchanger plates 4 and the first endplate 2 will be transferred to the ground via a second or lower guidingelement 7 b and a guiding rail 12. The upper guiding element 7 a and thelower guiding element 7 b are preferably identical to reducemanufacturing costs, but different shapes are also possible. In theshown embodiment, see e.g. FIG. 6, the lower external geometry 10 of theguiding element 7 b corresponds to an internal shape 16 of the guidingrail 12 enabling the guiding element 7 b to be secured to the guidingrail 12 and to be movable along the guiding rail 12. In someapplications the plate heat exchanger 1 is arranged on frame, whichfully or partially supports the guiding rail 12.

The upper guiding element 7 a extends through an aperture 8 of uppermostportion of the first end plate 2 so that the first end plate 2 can bemovable relative to the upper guiding element 7 a. Similarly extends thelower guiding element 7 b through an aperture 17 of the lowermostportion of the first end plate 2. Both the lower guiding element 7 b andthe upper guiding element 7 a only guides the first end plate 2, whereasthe load of the first end plate 2 is carried by the guiding rail 12 uponwhich the first end plate 2 rests. The heat exchanger plates 4 rest onthe lower guiding element 7 b and is guided laterally by the upperguiding element 7 a.

Each guiding element 7 a, 7 b comprise two parts 13 a, 13 b; 14 a, 14 b(see FIG. 3) to enable the guiding of the heat exchanger plates 4 duringthe opening and closing process of the plate heat exchanger 1 and thusenabling an outer guiding element part 14 a, 14 b to be removed when theheat exchanger plates 4 and the first end plate 2 are tighten togetherto form the operational plate heat exchanger 1, and applying nuts 6 ontothe tightening bolt 5 a, 5 b to keep the first end plate 2 in place andthe heat exchanger plates 4 tighten together between the first end plate2 and the second end plate 3. The length of the inner guiding elementpart 13 a, 13 b is preferably slightly less than the lengthcorresponding to the total thickness of all the heat exchanger plates 4in the package of plates and the first end plate 2. The length of theouter guiding element part 14 a, 14 b is preferably slightly less thanthe remaining free end of the tightening bolt 5 a, 5 b when the innerguiding element part 13 a, 13 b has been arranged onto the tighteningbolt 5 a, 5 b.

The upper guiding element 7 a can be provided with wear protectionarrangement to reduce the wear from the heat exchanger plates 4. Thewear protection arrangement can be of a plate or rubber material or anyother suitable material, and is preferably clamped onto the upperguiding element 7 a.

The guiding element 7 a, 7 b has an upper portion formed as an externalgeometry 19 having a width corresponding to the opening width of thecut-out 11 of the heat exchanger plates 4 and the apertures 8, 17 of thefirst end plate 2. Thereby both the upper guiding element 7 a and thelower guiding element 7 b can guide the first end plate 2 laterally,whereas the load of the first end plate 2 is carried by the guiding rail12. The upper guiding element 7 a and the lower guiding element 7 b willalso guide the heat exchanger plates 4 laterally by the externalgeometry 19 of the guiding elements 7 a, 7 b and the lower guidingelement 7 b will carry the load of the heat exchanger plates 4. The loadis transferred directly to the guiding rail 12 and further to theground. The external geometry 10 of the lower portion of the upperguiding element 7 a guides the heat exchanger plates 4 and serves atilting protection for the heat exchanger plates 4, when the plate heatexchanger 1 is open.

It is also possible that the upper guiding element 7 a fully orpartially carries the load of the heat exchanger plates 4 by theexternal geometry 10.

In FIGS. 5-6 the guiding element 7 a, 7 b and the guiding rail 12 isshown in more details, partial enlargement B and C of FIG. 4, as theyare arranged in the plate heat exchanger 1. One advantage of thesuggested guiding profile 7 a, 7 b is that the same component can beused both as a carrying and guiding bar in the upper section of theplate heat exchanger 1 as well as carrying and guiding bar in the lowersection of the plate heat exchanger 1. The guiding rail 12 serves as aweight transferring element, which also enables that the lower outerguiding element 14 b can be removed when the heat exchanger plates 4 andthe first end plate 2 are tighten together so that a nut 6 can bearranged on the lowermost tightening bolt 5 b in abutment with the firstend plate 2 and to keep the plate heat exchanger 1 in the closedoperational mode.

As shown in FIG. 1-2 the plate heat exchanger 1 can also be providedwith a support device 15 to enable the plate heat exchanger 1 to beopened in an easy way, which support device 15 is provide at the freeend of the tightening bolts 5 a, 5 b and kept in place by nuts 20. Thesupport device 15 extends between the two tightening bolts 5 a and 5 b,and ensures that distance between the two tightening bolts 5 a and 5 bis invariable and that forces affecting the upper tightening bolt 5 aare transferred to the ground. The further details of function andoperation of the support device 15 will be described in connection withthe description of the opening and closing process of the plate heatexchanger 1.

Now the opening of the plate heat exchanger 1 will be described. InFIGS. 1 and 2 the plate heat exchanger 1 is operational mode. Forenabling maintenance such as cleaning, repairing, replacing heatexchanger plates etc., the plate heat exchanger 1 can be opened. Thenuts 20 are screwed off and the supporting device 15 and the outerguiding elements 14 a, 14 b are taken away of the tightening bolts 5 a,5 b. The nuts 6 arranged to the tightening bolts 5 a, 5 b are screwedoff and the outer guiding elements 14 a, 14 b are again arranged ontothe free parts of the tightening bolts 5 a, 5 b and pushed abutmentagainst the inner guiding elements 13 a, 13 b. The package of heatexchanger plates 4 and the first end plate 2 is still kept together bythe further tightening bolts 5 c. The supporting device 15 is once againmounted onto the free parts of the upper and lower tightening bolts 5 a,5 b. The supporting device 15 is supported to the ground via the outerguiding element 14 b and the guiding rail 12. The nuts 20 are broughtupon the tightening bolts 5 a, 5 b and tightened. The further tighteningbolts 5 c are demounted. As the tightening bolts 5 c are released thefirst end plate 2 and the heat exchanger plates 4 may thereafter bemoved along the guiding elements 7 a, 7 b. Hereby an open mode ofservice of the plate heat exchanger 1 is attained, when the heatexchanger plates 4 are situated between the end plates 2, 3 may beseparated for cleaning and one or several heat exchanger plates 4 may betaken out and eventually new ones put in without the need for demountingof the rest of heat exchanger plates 4. Closing or tighten together theplate heat exchanger 1 into operational mode is executed in an analogousreversed way.

The supporting device 15 is a bar, a plate iron or the like with asufficient length to be able to hold the uppermost and lowermosttightening bolts 5 a, 5 b at a correct distance in relation to eachother and at the same time in the open mode of service for the plateheat exchanger 1 to be able to serve as a supporting device 15 for thewhole plate heat exchanger 1 together with the second end plate 2. Itfurther ensures that forces affecting the upper tightening bolt 5 a aretransferred to the ground via the lower tightening bolt 5 a.

The guiding element 7 a, 7 b and the guiding rail 12 are preferably madeof an extrudable material such as a plastic or aluminum profile, but canalso be made of any other suitable manufacturing method or material.

The invention is not limited to the embodiments described above andshown on the drawings, but can be supplemented and modified in anymanner within the scope of the invention as defined by the enclosedclaims.

1. A plate heat exchanger comprising first and second end plates, and acore of heat exchanger plates arranged between the first and second endplates, whereby a plurality of threaded tightening bolts extend betweenthe first and second end plates and are arranged, together with nuts, tohold the end plates at a desired distance from each other in order tohold the core of heat exchanger plates together, wherein at least oneguiding element for guiding the first end plate and the heat exchangerplates relatively relative to the second end plate is releasablyarranged on at least one of the threaded tightening bolts, which guidingelement extends through an aperture in the first end plate, and whereinthe at least one guiding element is provided with a through-hole toreceive the at least one of the threaded tightening bolts and the atleast one guiding element has an external geometry corresponding to acut-out of the heat exchanger plates and the first end plate.
 2. Theplate heat exchanger according to claim 1, wherein the plate heatexchanger includes two guiding elements, the first guiding element beingarranged in an upper portion of the plate heat exchanger and the secondguiding element being arranged in a lower portion of the plate heatexchanger.
 3. The plate heat exchanger according to claim 2, wherein thefirst and second guiding elements have an identical cross sectionprofile.
 4. The plate heat exchanger according to claim 2 or claim 3,wherein the second guiding element further is provided with a guidingrail for movably receiving the second guiding element.
 5. The plate heatexchanger according to claim 4, wherein the guiding rail for movablyreceiving the second guiding element is fully or partially supported bythe ground.
 6. The plate heat exchanger according to claim 1, whereinthe at least one guiding element includes two separate parts.
 7. Theplate heat exchanger according to claim 4, wherein the guiding elementsand the guiding rail are made of an extrudable material.
 8. The plateheat exchanger according to claim 1, wherein the at least one guidingelement is movable along the tightening bolts and where one part of theguiding element is removable as the heat exchanger plates are tightenedtogether by the first end plate to form the plate heat exchanger, andwhere subsequently the removed one part of the guiding element can bearranged on a free portion of the tightening bolt outside the first endplate.
 9. The plate heat exchanger according to claim 1, wherein asupporting device is releasably arranged at a distance from the firstend plate at the end of the at least one tightening bolt, and extendsbetween two of the tightening bolts.
 10. A plate heat exchangercomprising first and second end plates, and a core of heat exchangerplates arranged between the first and second end plates, whereby aplurality of threaded tightening bolts extend between the first andsecond end plates and are arranged, together with nuts, to hold the endplates at a desired distance from each other in order to hold the coreof heat exchanger plates together, wherein at least one guiding elementfor guiding the first end plate and the heat exchanger plates relativeto the second end plate is releasably arranged on at least one of thethreaded tightening bolts, which guiding element extends through anaperture in the first end plate, and wherein the heat exchanger platesrest on the at least one guiding element and where the first end platerests on a guiding rail, upon which guiding rail the at least oneguiding element is movably received.
 11. The plate heat exchangeraccording to claim 10, wherein an upper located guiding element onlyguides the heat exchanger plates and the first end plate.